Blender saves a new file every time
These are backup files created by Blender and are fairly normal.

Excerpt from the wiki


  Save and Auto Save
  
  ...To reduce the chance of
  losing files when those events occur, Blender can use an Autosave
  function. The File tab of the User Preferences window allows you to
  configure the two ways that Blender provides for you to regress to a
  previous version of your work...